US Secretary of State Hillary Clinton wraps up a tour of Asia today dominated by thorny disputes, as she sees signs of progress in working through problems with emerging powers China and India.

Clinton's week-long trip was dominated by a crisis in China over dissident Chen Guangcheng, who took refuge in the US embassy in Beijing, and ended in India where usually friendly US ties have been tested by disagreement on Iran.

Clinton, who meets Indian Foreign Minister S M Krishna today before returning to Washington, has been pressing India to buy less oil from Iran as a way to pressure the Islamic regime over its contested nuclear programme.

India has bristled at threatened US sanctions against countries that keep buying oil from Iran, in one of the most open feuds between the world's two largest democracies since they began to move closer in the late 1990s.

But Indian companies have been quietly reducing their purchases, with US officials voicing hope that pressure on the marketplace will work.

Clinton was in New Delhi to prepare for the US-India Strategic Dialogue, held each year since 2010, which will take place next month in Washington.